托福口语 Task 4

Today we're going to talk about a fascinating concept in animal behavior called 'sensory exploitation.' This is a theory that explains why some animals have evolved particular traits that seem to appeal to the opposite sex. The main idea is that these traits don't necessarily evolve because they signal good genes or health, but because they exploit pre-existing sensory biases in the receiver. Let me give you two examples. First, consider the guppy. Female guppies have an innate preference for the color orange, likely because in their natural environment, orange is associated with a food source—small orange-colored crustaceans. Males have evolved bright orange spots to exploit this bias, making them more attractive to females. Second, take the túngara frog. Female frogs are naturally attracted to a specific low-frequency 'chuck' sound, which resembles the sound of a nearby predator or a rival male. Males have added an extra 'chuck' to their call to exploit this sensitivity, thereby increasing their chances of mating. So, in both cases, the traits evolved not because they indicate quality, but because they tap into pre-existing preferences.